Copper base alloy



UNITED STATES PATENT OFFICE COPPER BASE ALLOY Cyril Stanley Smith, Cheshire, and Earl W. Palmer, Waterbury, Conn., assig'nors to The American Brass Company, Waterbury, Conn, a. corporation of Connecticut No Drawing. Application October 11, 1937, Serial No. 168,422

4 Claims. (Cl. 75-160) The alloys of copper, silicon and manganese Specific alloys which have been found very find extensive commercial application wherever satisfactory are as follows: strong corrosion resistant alloys of copper are An alloy containing approximately 3 per cent desired. They cast and hot work easily and are silicon, 1 per cent manganese, l per cent of either 5 characterized by ready weldability. We have zinc or tin; 0.03 per cent of either sodium,'lithium 6 found that their characteristic properties of castor potassium; and balance copper. ability and weldability can be still further en- Also an alloy containing approximately 3 per hanced by additions of an alkali metal such as cent silicon, 1 per cent manganese, 1 per cent lithium, sodium or potassium. This addition not cadmium, 0.02 per cent of either sodium, lithium 10 only gives a more fluid metal, and produces a betor potassium; and balance copper. l0

ter surface on the casting, but it also has a The addition of alkali metal greatly improvesmarked effect on removing gases and thus makes the casting qualities of the metal and makes it it easier to obtain castings free from porosity or easier to obtain sound castings in either metal sponginess. or sand molds. It has no harmful effect on Because of the high reactivity and volatility the ductility of the alloys either hot or cold un- 15 of the alkali metals in the elemental state we less present in excess. prefer to make the addition in the form of an In addition to good casting qualities, the alalloy with any one or more of the elements tin, loy of copper, silicon, manganese and an alkali cadmium or zinc, none of which elements in reametal possesses qualities that make it particusonable amounts is harmful to the properties of larly adapted to modern methods of fabrication. 20 the alloys and, indeed, may be beneficial. Alloys The alloy may be hot or cold rolled, hot or containing between 0.5 and 5 per cent of one or cold extruded, hot or cold forged, hot or cold more of these alkali metals in conjunction with pressed, hot or cold drawn. Very desirable casteither tin or cadmium or zinc, or mixtures of ings may also be made from this composition these, are reasonably stable in contact with air, when the fluid metal is cast in sand molds or have a melting P t low r t a the pp r-siflpermanent or chill molds. Die castings may also con-manganese alloy and are readily added to be made. The alloy may be produced in the these alloys without undue oxidization or volaform of wire, cables, rods, sheets, tubes, pipe, tilization loss. These master alloys are readily shapes and various formed articles made from and safely made by melting the tin, cadmium these various items,

or zinc and dissolving therein the sodium, potas- The composition is relatively free from season sium or lithium. The amount of this master alcracking and has a high resistance to corrosion, loy will be greater than 0.1 per cent and less both atmospheric corrosion and general corrohan 5 per ent f h w i h of h pp sion. The alloy may be used in chemical works silicon-manganese alloy when zinc or tin is used, where high resistance to corrosion and wear are 35 and not greater than 2 per cent when cadmium required. Exact details would depend, of course, is used, because largeramounts of cadmium emon the exact type of corrosion and wear. brittle the alloy and make it practically imD The alloy may be readily machined and also sible to work it either hot or cold. It is somer011 threaded. The composition may be made 40 times advisable to add a propert on o copper into bolts, screws, nuts, etc., where bending, 40

not exceeding 50 pe c nt to this ter alloy forming, heading, hot or cold, are required. to reduce its volatility further. Welded fabricated structures may also be made It is p f ra to melt the alloy of pp from the composition, which may be welded elecsilicon and manganese in the cus ry W ytrically in an autogenous manner, also spot either from Scrap from Virgin metal, and then welded or brazed. The fabricated structures may 45 to add the proper amount of the master alloy also be made by gas welding, autogenous weldcontaining the alkali metal. The amount of aling or brazing. Fabricated structures may be kali metal introduced should be not over .25 made by soldering. This alloy is particularly depercent and is pre rab y about P C sirable from the standpoint of welding since it is J0 but it may be as low as about 0.005 per cent practically self-fluxing and may be joined either and still produce a material improvement. The by resistance are or flame welding with a filler amount of tin or zinc in the resultant alloy rod of similar or different material. should not exceed about 5 per cent, or if cad- It is, obvious that this alloy may be used for mium is used to carry in the alkali metal not all purposes in which wires, cables, rods, sheets,

- over 2 per cent should remain in the final alloy. tubes, pipes, shapes and formed articles are ordi- 55 corrosion, disintegration, 'etc., as copper, brass and other copper alloys and consequently may be substituted in making the articles usually produced from copper and its alloys. It has high resistance to corrosion in the atmosphere and in both hot and cold, fresh and salt water.

The alloy is particularly suited for making springs, both from wire and rods as well as strips and sheets.

In addition to welding readily, both electrically and by the gas method, the alloy makes very desirable welding or filler material for both electric and gas welding, also made into powder for brazing. electrodes, welding rods, filler rods, brazing rods, brazing solder, etc. The alloy also responds to heat treatment. It is particularly good in welding iron and steel, cast ironand other iron alloys.

Wire may be Woven into screens or similar materials, such as Fourdrinier wire cloth or insect screens.

The alloy may be used in coating other metals such as to make duplex metal.

The alloy may becolored or coated itself by electrical or chemical methods or a combination of both.

tion wherein its strength, ductility and corrosion resistance is of advantage. It takes on a good polish and is of attractive color and appearance.

In cases where high machinability is desired, additions of 0.01 to 1 per cent of lead, sulphur, selenium or tellurium may be made. Lead additions render the alloy hot short but the additions of sulphur, selenium, or tellurium have no such eflect.

Because of the rapid volatilization of the so- Sometimes such material is termed In short the alloy is suitable for any applicadium it is essential to add it in the form of a master alloy as above disclosed. Potassium and lithium may, however, be added in the elemental form without much loss and in this case the presence in the alloy of zinc, cadmium, or tin is not necessary. The element potassium has been found to be the most eflective of the group in improving the fluidity of the molten metal. Compositions which we have found to be particularly desirable are: Silicon 3.0%, Manganese 1.0%, Potassium 0.03%, balance copper; and another Silicon 3.0%, Manganese 1.0%, and Lithium 0.03%, balance copper. However, the amount of lithium or potassium may vary between 0.005 and 0.25% as described above.

Having thus set forth the nature 01' our invention, what we claim is:

1. A copper base alloy characterized by being workable both hot and cold containing 0.1 to 5 per cent silicon, 0.1 to 5 per cent manganese, 0.005 to 0.25 per cent of an alkali metal from the group consisting of lithium and potassium; and balance copper.

2. A copper base alloy containing approximately 3 per cent silicon, 1 per cent manganese, 0.02 per cent of an alkali metal from the group consisting of lithium and potassium, and balance copper.

3. A copper base alloy containing 0.1 to 5 percent silicon, 0.1 to 5 percent manganese, 0.005 to 0.25 percent of an alkali metal from the group consisting of sodium, lithium and potassium, and balance substantially all copper or copper and not over 5 percent of a carrier metal for the alkali metal.

4. A copper base alloy containing approximately 3 percent silicon, 1 percent manganese,

not over 5 percent of a carrier metal for the alkali metal.

CYRIL STANLEY SMITH. EARL W. PALMER. 

